All Golems should be, one point wonders for those starting out in Golems. But when one becomes more experienced there are additional possibilities if those skills are to be developed further.
One example would be the Golemancer. I'm considering to build a one to max Clay, Blood, Iron, Fire, and Golem Mastery as well as develop on Summon Resist. Clay and Fire will be maxed first, and Blood and Iron Golem (gives +Defense synergy) will be maxed last because Golemmancers are already not very effective by themselves, and Attack Rating and Damage are most desireable in a Golem for maximum offense.
The other main reason for building a Golemancer is to create a very powerful Iron Golem (e.g E Last Wish Thunder Maul, E Beast Decapitator). The idea is to maximize the damage possible on an Iron Golem in terms of base damage and attack rating, even if it means only a small boost as you will see why. Then, the survivability of the Golem is increased after with points on Golem Mastery, Blood (Life) and Iron (Defense) synergies. What was previously a small boost in damage is applied permanently to a permanent Golem.
Golems are not very strong alone. Clay Golem speeds up the effectiveness of your other minions by slowing monsters down, Blood Golem drains Life which reduces drinking potions and increases the amount of time you can stay in battle. Iron Golem can inflict damage indirectly from thorns, or directly if it is made out of a good weapon. Fire Golem attracts monsters, and increases the survival of the other minions and does some Fire damage. Usually, only one of these Golems is out at a time.
But it is the only tool that Necromancers have. Thus for a Necromancer focusing on Golems, it is in one's best interest to use more than one Golem at once if necessary. Iron Golem is difficult to be summoned in conjunction with other Golems so it will be ruled out for now. But Clay, Blood, Fire Golem are still viable in a difficult battle. Summon Clay first, once the monsters have been slowed, use Fire to attract the already slowed monsters to further increase one's chance to survive as well of that of the army's. If the monsters are 1) Fire Immune 2) heavy on Poison/Magic damage or 3) if the Summoner is low on health, switch to Blood Golem which can do Physical damage instead and has some inherent Poison and Magic resistance, and has a life leech that can steal all the life back in one hit, at high skill levels.
Big bonus for Blood Golem is that Elemental damage will not drain life away from you.
This would apply equally in PvP for all types of necromancers. Use Clay first, slow them down then use Fire to deal additional damage or to finish them off in the case of Poison. Note that although Fire Golem may not be great against monsters except Cold Immunes, it can still be useful in a Battle as it means 200 additional damage for those without Lower Resist, and 400 for Necromancers with the Lower Resist + Conviction ability. Note that not all players have 75% Fire Resist, so one is able to take advantage of a lower Fire resistance.
There are no skills that are negative, and likewise there is no such thing as putting points in a certain skill will count against you (unless in special exceptions like Bone Armor where you could put points on Bone Wall/Prison instead). There are only good skills, and better skills. Basically, there are only different skills, each with its own unique properties. We work from there because each build is different and cannot be compared to each other if widely dissimilar.